Preparation method and application of water-based fluorescent probe

Abstract

The invention discloses a preparation method and application of a water-based fluorescent probe, and relates to the field of environment and water quality monitoring, in particular to a preparation method of a water-soluble fluorescent probe L and tandem detection of aluminum ions and sodium pyrophosphate. The defect that an existing fluorescent probe for detecting aluminum ions and sodium pyrophosphate needs an organic solvent as a test medium in the application process can be overcome. A preparation method of the probe L comprises the following step: carrying out reflux reaction on isoniazide and 2-hydroxy-4-(3-hydroxypropoxy) benzaldehyde in absolute ethyl alcohol to prepare the fluorescent probe L. The fluorescent probe L prepared by the invention realizes specific fluorescence'off-on-off 'detection on aluminum ions and sodium pyrophosphate in a water-based environment, and has the advantages of good selectivity, high sensitivity and environmental protection. The fluorescent probe L can be applied to detection of aluminum ions and sodium pyrophosphate in metal aluminum part water-based cleaning solution industrial wastewater.

Description

Technical Field

[0001] The present invention relates to the field of analytical detection, and particularly to a preparation method of a water-soluble fluorescent probe and its application in sequential detection of aluminum ions and sodium pyrophosphate. Background Art

[0002] Aluminum is the most abundant metallic element on earth. It has advantages such as easy processing, strong corrosion resistance, and convenient use, and has now been widely used in daily life. However, excessive intake of aluminum ions can cause loss of appetite and osteoporosis. If deposited in the brain, it may cause Alzheimer's disease or affect the intellectual development of infants and young children. Therefore, the World Health Organization (WHO) recommends that the daily aluminum intake should not exceed 3 - 10 mg, and the upper limit of aluminum content in drinking water is 7.4 μmol / L. In addition, aluminum pollution is not only harmful to humans, but also affects plant growth. Plants will show signs of toxicity when the aluminum concentration reaches 10 - 20 mg / kg. The extensive application of aluminum in fields such as alloy materials, food, and pharmaceuticals will cause aluminum ions to enter the ecological environment through waste water discharge and other channels. Therefore, it is very important to realize the detection of Al 3+ content.

[0003] As a biological functional component, pyrophosphate (PPi) is the hydrolysis product of adenosine triphosphate and other nucleotides, and plays an important role in life activities such as DNA and RNA polymerization and replication, energy transfer, and various metabolisms. At the same time, PPi can also be used as a food additive, which can increase the probability of protein film formation and improve the quality of meat products. In addition, in industrial production, PPi can also be used as an effective component of metal cleaning agents, with functions such as adjusting pH and stabilizing the system. However, excessive PPi in the environment can cause serious water eutrophication and pollution, posing a great threat to aquatic organisms and human health. Establishing an accurate and sensitive PPi detection method is very important for environmental monitoring and biosafety.

[0004] Although traditional analytical methods (such as electrochemistry, colorimetry, spectrophotometry, ion chromatography, etc.) have high effectiveness and precision, there are also problems such as complex and time-consuming sample pretreatment processes, long detection times, high costs, and inapplicability to on-site detection. It is difficult to meet the requirements of rapid analysis in the detection of samples, so it is very necessary to establish a rapid and sensitive analytical detection method. As an important analytical tool, fluorescence probe detection methods have been widely used due to their low cost, high selectivity, high sensitivity, and ease of operation. Currently, most analytes such as metal ions, anions, and reactive substances are water-soluble. To meet the test requirements, eliminate the need for organic solvents, and make the detection process safer and more environmentally friendly, it is particularly important to develop water-soluble fluorescence probes. In the present invention, an imine bond (C=N) is used as the recognition group, and more hydrophilic groups such as hydroxyl groups and nitrogen atoms are introduced into the structure to improve the water solubility of the probe. Based on the above ideas, a water-soluble fluorescence probe L was successfully designed and prepared, which can serially detect aluminum ions and sodium pyrophosphate in an aqueous environment, belonging to the fluorescence "off-on-off" type detection. The detection process has good selectivity, high sensitivity, is easy to operate, green and environmentally friendly, and has good application prospects in the field of monitoring wastewater from metal aluminum part cleaning solutions. Summary of the Invention

[0005] The present invention aims to solve the deficiency that organic solvents are required as detection media in the detection of aluminum ions and sodium pyrophosphate, and provides a preparation method and application of a water-soluble fluorescence probe for serially detecting aluminum ions and sodium pyrophosphate.

[0006] A water-based fluorescence probe L of the present invention has the following molecular structure:

[0007]

[0008] The synthesis route of the above fluorescence probe L is as follows:

[0009]

[0010] A preparation method of a water-based fluorescence probe L in the present invention is: reacting isoniazid with 2-hydroxy-4-(3-hydroxypropoxy)benzaldehyde by refluxing in absolute ethanol.

[0011] The application of the fluorescence probe L of the present invention in the sequential detection of aluminum ions and sodium pyrophosphate.

[0012] Preferably, the probe L can achieve continuous fluorescence "off-on-off" detection of aluminum ions and sodium pyrophosphate.

[0013] Preferably, the complex of the probe L and aluminum ions can resist common phosphorus-containing anions H₂PO₄ - , HPO₄ 2- , and PO₄ 3-interference

[0014] Preferably, the probe L can be used for detecting aluminum ions and sodium pyrophosphate in the wastewater of the water-based cleaning solution for metal aluminum parts.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1) The fluorescent probe L prepared by the present invention can achieve tandem detection of aluminum ions and sodium pyrophosphate under the same test conditions, and can resist the interference of common phosphorus-containing anions H2PO4 - , HPO4 2- and PO4 3- during the detection, and has good selectivity.

[0017] 2) The fluorescent probe L in the present invention can play a detection role in a nearly aqueous environment, solving the deficiency that the existing fluorescent probes for detecting aluminum ions and sodium pyrophosphate need organic solvents as test media in applications, and having the application advantage of environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 1H NMR spectrum of the fluorescent probe L prepared by the present invention; 1

[0019] Figure 2 FT-RT spectrum of the fluorescent probe L prepared by the present invention;

[0020] Figure 3 Selectivity of the fluorescent probe L for recognizing metal ions;

[0021] Figure 4 Linear relationship diagram of the fluorescence response of the fluorescent probe L to aluminum ions with different concentrations;

[0022] Figure 5 Job’s plot curve of the fluorescent probe L for Al 3+ ;

[0023] Figure 6 Selectivity recognition diagram of the complex L-Al 3+ for different anions;

[0024] Figure 7 Influence diagram of coexisting anions on the recognition of sodium pyrophosphate by the complex L-Al 3+ ;

[0025] Figure 8 Linear relationship diagram of the fluorescence response of the complex L-Al 3+ to sodium pyrophosphate with different concentrations. DETAILED DESCRIPTION OF THE INVENTION

[0026] ​The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination between the specific embodiments.

[0027] Specific Embodiment 1: The molecular structure of a water-based fluorescent probe L in this embodiment is:

[0028]

[0029] Specific Embodiment 2: The preparation method of the fluorescent probe L includes the following steps: Isoniazid and 2-hydroxy-4-(3-hydroxypropoxy)benzaldehyde are refluxed in ethanol for 10 h; the reaction product is filtered, washed, and dried to obtain the fluorescent probe L.

[0030] Specific Embodiment 3: The application of the fluorescent probe L in this embodiment for the tandem detection of aluminum ions and sodium pyrophosphate.

[0031] Specific Embodiment 4: The specific method for the tandem detection of aluminum ions and sodium pyrophosphate by the fluorescent probe L in this embodiment is as follows:

[0032] 1. Dissolve the fluorescent probe L in water to prepare a 1.0×10 -5 mol / L probe solution. Under the action of 379 nm excitation light, measure the fluorescence emission peak intensity of the fluorescent probe at 470 nm; add an aqueous solution of aluminum nitrate to the probe solution and measure the fluorescence emission peak intensity of the fluorescent probe at 470 nm.

[0033] 2. Incubate the fluorescent probe L solution with aluminum nitrate for 30 s, then add an aqueous solution of sodium pyrophosphate to the system, and under the action of 379 nm excitation light, measure the fluorescence emission peak intensity value of the system at 470 nm.

[0034] Specific Embodiment 5: The difference between this embodiment and Specific Embodiment 3 or 4 is that the fluorescent probe L can achieve continuous fluorescence "off-on-off" detection of aluminum ions and sodium pyrophosphate. Others are the same as Specific Embodiment 3 or 4.

[0035] Specific Embodiment 6: The difference between this embodiment and Specific Embodiment 4 is that during the detection of sodium pyrophosphate by the complex L-Al 3+ it can resist common anions such as PO4 3- , ClO - , SO3 2- , SO4 2- , HSO 4- , H2PO4 - , HPO4 <{ 2- , NO 3- , Br - , I - , HCO3 - , CO3 <{ 2-, Cl - , CH3COO - , Cr2O7 2- interference. Others are the same as in the fourth specific implementation manner.

[0036] Seventh specific implementation manner: The difference between this implementation manner and the fourth specific implementation manner is that the detection limit of the probe L for aluminum ions is as low as 9.8×10 -8 mol / L and the detection limit of the complex L-Al 3+ for pyrophosphate is as low as 2.7×10 -7 mol / L. Others are the same as in the fourth specific implementation manner.

[0037] Eighth specific implementation manner: The difference between this implementation manner and the third specific implementation manner is that the probe L is used for the detection of aluminum ions and sodium pyrophosphate in the wastewater of the metal aluminum part cleaning solution. Others are the same as in the third specific implementation manner.

[0038] The following is a detailed description of the implementation of the present invention. The following implementations are carried out on the premise of the technical solution of the present invention, and detailed implementation plans and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0039] Example 1: The preparation method of the fluorescent probe L in this example is carried out according to the following steps:

[0040] Add isoniazid (0.2000 g, 1.46 mmol), 2-hydroxy-4-(3-hydroxypropoxy)benzaldehyde (0.3145 g, 1.60 mmol) and 15 mL of absolute ethanol into a 50 mL three-necked flask, and reflux for 10 h; after cooling to room temperature, filter under vacuum, wash with absolute ethanol, and dry to obtain the fluorescent probe L (0.3561 g), and the yield is 76%. 1 1H NMR (300 MHz, DMSO-d6) δ 12.19 (s, 1H), 11.38 (s, 1H), 8.79 (d, J = 5.3 Hz, 2H), 8.58 (s, 1H), 7.83 (d, J = 5.4 Hz, 2H), 7.48 (d, J = 8.6 Hz, 1H), 6.58–6.43 (m, 2H), 4.57 (s, 1H), 4.06 (t, J = 6.4 Hz, 2H), 3.55 (t, J = 6.2 Hz, 2H), 1.89–1.82 (m, 2H) ppm. IR (KBr), v / cm -1 : 3109, 3041, 2956, 2865, 1762, 1633, 1513, 1361, 1280, 1168, 1143, 1039, 993, 850, 690. The 1 1H NMR spectrum and FT-RT spectrum of the probe L are as shown in Figure 1 ,2 as shown

[0041] Example 2: Preparation of the probe L solution was carried out according to the following steps:

[0042] Accurately weigh 3.1 mg of probe L and prepare a stock solution A of the probe at 1.0×10 -2 mol / L with DMF; Take 50 μL of stock solution A of the probe and make up the volume to 50 mL with an aqueous solution to prepare a probe solution B of 1.0×10 -5 mol / L for later use.

[0043] Example 3: Selective recognition of aluminum ions by the probe L in this example was carried out according to the following steps:

[0044] Each time, take 3 mL of solution B in a cuvette and successively add 3 eq. of Al 3+ , Ba 2+ , Cd 2+ , Co 2+ , Zn 2+ , Ag + , Ca 2+ , Cr 3+ , K + , Al 3+ , Fe 3+ , Mg 2+ , Pb 2+ , Na + , Ni 2+ , Cs + , Ce 3+ , Li + , Hg 2+ , Bi 2+ aqueous solutions. At an excitation wavelength of 379 nm, measure the fluorescence emission peak intensity value of the fluorescent probe L at 470 nm, with slit widths of 5 nm and 10 nm. The results are as Figure 3 shown. The fluorescent probe L itself has no fluorescence. After adding Al 3+ , the fluorescence increases by 37 times, while adding other metal ions does not cause obvious fluorescence changes, indicating that the fluorescent probe L shows a specific recognition effect on Al 3+ .

[0045] Example 4: The detection limit of the fluorescent probe L for aluminum ions in this example was carried out according to the following steps:

[0046] Take 3 mL of solution B with a concentration of 1.0×10 -5 mol / L. Each time, add 3 μL of an aluminum ion aqueous solution with a concentration of 1×10 -3 mol / L and measure the fluorescence intensity. Plot the aluminum ion concentration on the abscissa and the fluorescence intensity on the ordinate. The results are as Figure 4As shown, when the concentration of aluminum ions is within 0 μM - 10 μM, the fluorescence intensity continuously increases with the increase of the aluminum ion concentration. There is a good linear relationship between the fluorescence intensity and the aluminum ion concentration, and the fitting equation is y = 226.9060x - 165.1933, R 2 = 0.997. According to the detection limit calculation formula 3σ / k, the detection limit of the probe L for aluminum ions is calculated to be 9.8×10 -8 mol / L. Thus, it can be seen that the probe L can achieve trace detection of aluminum ions.

[0047] Example 5: The complexation ratio of the probe L with aluminum ions in this example is carried out as follows:

[0048] Take a solution B with a concentration of 1.0×10 -5 mol / L and an aluminum ion aqueous solution of 1×10 -3 mol / L, and keep the total concentration of the probe L and aluminum ions in the system at 1×10 -5 mol / L unchanged. By changing the equivalent ratio of the probe L and aluminum ions, their fluorescence intensities are measured respectively, and a Job’s Plot curve graph is drawn. As Figure 5 shown, when the mole fraction of aluminum ions is 0.54, the fluorescence intensity shows an inflection point, indicating that the complexation ratio of the probe L with Al 3+ is 1:1.

[0049] Example 6: The selective recognition of sodium pyrophosphate by the complex L - Al 3+ is carried out as follows:

[0050] Take 3 mL of solution B with a concentration of 1.0×10 -5 mol / L and add 1 eq. of aluminum ion solution. After incubating for 30 s, the complex L - Al 3+ system solution is obtained. Then, 3 eq. of aqueous solutions of PO4 -2 , ClO 3- , SO3 - , SO4 2- , SO4 2- , HSO 4- , H2PO4 - , HPO4 2- , NO 3- , Br - , I - , HCO3 - , CO3 2- , Cl - , CH3COO - , Cr2O7 2- are added in sequence, and their fluorescence intensities are measured at an excitation wavelength of 379 nm. The results are as Figure 6As shown, after adding sodium pyrophosphate, the fluorescence of the system is quenched 23 times, although PO4 3- The addition of ions will cause partial quenching of fluorescence, but still show obvious fluorescence enhancement. When other anions are added, the fluorescence intensity does not change significantly. It can be seen that the complex L-Al 3+ The system achieves specific recognition of sodium pyrophosphate.

[0051] Example 7: Complex L-Al 3+ The identification and anti-interference of sodium pyrophosphate are carried out according to the following steps:

[0052] Take 3mL of the solution with a concentration of 1.0×10 -5 mol / L solution B was added with 1eq. of aluminum ion solution and incubated for 30s to obtain the complex L-Al 3+ system. 3eq. of 1×10 -2 mol / L PO4 3- , ClO - 、SO3 2- 、SO4 2- 、HSO 4- 、H2PO4 - 、HPO4 2- 、NO 3- Br - , I - 、HCO3 - 、CO3 2- 、Cl - 、CH3COO - 、Cr2O7 2- The fluorescence intensity of the aqueous solution was recorded at an excitation wavelength of 379 nm, and then 3 eq. of sodium pyrophosphate aqueous solution was added, and the changes in fluorescence intensity were observed and recorded. Figure 7 As shown, in the presence of other anions, the complex L-Al 3+ The fluorescence of the system still showed a significant enhancement, but after adding sodium pyrophosphate, the fluorescence quenching was achieved. 3+ The system recognized that sodium pyrophosphate had no interference.

[0053] Example 8: Complex L-Al 3+ The detection limit of sodium pyrophosphate was determined by the following steps:

[0054] The concentration is 1.0×10 -5 mol / L solution B was added with 1eq. of aluminum ion solution and incubated for 30s to obtain the complex L-Al 3+ System solution C is set aside. Take 3 mL of solution C and add 3 μL of solution C at a concentration of 1×10 -3Sodium pyrophosphate aqueous solution at mol / L, detect and record the fluorescence intensity each time. The results are as Figure 8 shown. When the concentration of sodium pyrophosphate is within 0 μM - 5 μM, the fluorescence intensity of the complex system continuously weakens with the increase of the sodium pyrophosphate concentration. There is a good linear relationship between the fluorescence intensity and the sodium pyrophosphate concentration. The fitting equation is y = -394.8057x + 2141.3476, R 2 = 0.994. According to the detection limit calculation formula 3σ / k, the detection limit of the complex L - Al 3+ for sodium pyrophosphate is 2.7×10 -7 mol / L. This shows that the complex L - Al 3+ system can achieve trace detection of pyrophosphoric acid.

[0055] Example 9: Application of the probe in detecting AL 3+ and sodium pyrophosphate in the wastewater of metal aluminum parts cleaning solution

[0056] Examine the application of the probe in the water - based metal cleaning solution. Take 3 mL of the probe solution in a cuvette, then add 30 μL of the cleaning solution wastewater. Under the action of 379 nm excitation light, measure the fluorescence emission peak intensity of the fluorescent probe at 470 nm as 104.00 a.u. According to the fitting equation y = 226.9060x - 165.1933, the concentration of Al 3+ in the cleaning solution wastewater is 0.12 mmol / L.

[0057] Then use the complex L - Al 3+ to detect the concentration of sodium pyrophosphate in the cleaning solution wastewater. Take 3 mL of the L - Al 3+ system solution in a cuvette, then add 30 μL of the water - based metal cleaning solution wastewater. Under the action of 379 nm excitation light, measure the fluorescence emission peak intensity of L - Al 3+ at 470 nm as 159.4 a.u. According to the fitting equation y = -394.8057x + 2141.3476, the concentration of sodium pyrophosphate in the water - based metal cleaning solution wastewater is 0.50 mmol / L. These results indicate that the probe prepared by the present invention can be used for the detection of aluminum ions and sodium pyrophosphate in the wastewater of metal aluminum parts cleaning solution, and has good practical performance.

Claims

1. A water-based fluorescent probe, characterized in that The molecular structure of probe L is as follows:

2. The aqueous fluorescent probe according to claim 1, wherein The preparation method of probe L is as follows: Isoniazid and 2-hydroxy-4-(3-hydroxypropoxy)benzaldehyde are refluxed in absolute ethanol.

3. Application of the fluorescent probe L as claimed in claim 1 in the sequential detection of aluminum ions and sodium pyrophosphate.

4. The application according to claim 3, wherein Probe L can achieve sequential fluorescence "off-on-off" detection of aluminum ions and sodium pyrophosphate in a nearly hydrophilic environment.

5. The application according to claim 4, wherein Probe L and its aluminum ion complex can resist the interference of common phosphorus-containing anions H2PO4 - , HPO4 2- , and PO4 3- during the detection of sodium pyrophosphate.

6. The application according to claim 4, wherein Probe L can be used for the detection of aluminum ions and sodium pyrophosphate in the wastewater of the water-based cleaning solution for metal aluminum parts.

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